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  • 1
    Electronic Resource
    Electronic Resource
    Analytic representations suitable for numerical computation of some special functions (1980)
    Springer
    Numerische Mathematik 35 (1980), S. 163-174 
    Details
    ISSN: 0945-3245
    Keywords: AMS(MOS): 65B10 ; CR: 5.12
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary A procedure for deriving a convergent series, suitable for numerical computation, of some special functions defined by integrals is given. It uses a change of variable chosen so that the range of integration lies inside the circle of convergence of the new power series expansion of the integrand. An error analysis and numerical examples are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01396313
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  • 2
    Electronic Resource
    Electronic Resource
    Quadrature formulas obtained by variable transformation (1973)
    Springer
    Numerische Mathematik 21 (1973), S. 206-219 
    Details
    ISSN: 0945-3245
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract Quadrature formulas suitable for evaluation of improper integrals such as $$\int\limits_{ - 1}^1 {f(x)(1 - x)^{ - \alpha } (1 + x)^{ - \beta } dx,\alpha ,\beta〈 1} $$ are obtained by means of variable transformations κ=tanhu and κ=erfu, and subsequent use of trapezoidal quadrature rule. Error analysis is carried out by the method of contour integral, and the results are confirmed on several concrete examples. Similar formulas are also obtained to accelerate the convergence of infinite integrals $$\int\limits_\infty ^\infty {f(x)dx} $$ by means of variable transformations κ=sinhu and κ=tanu.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01436624
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  • 3
    Electronic Resource
    Electronic Resource
    EFFECTS OF HYPOXIC EXERCISE CONDITIONING ON WORK CAPACITY, LACTATE, HYPOXANTHINE AND HORMONAL FACTORS IN MEN (1999)
    Melbourne, Australia : Blackwell Science Pty
    Clinical and experimental pharmacology and physiology 26 (1999), S. 0 
    Details
    ISSN: 1440-1681
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: 1. Hypoxanthine is a purine degradation product and exercise plasma hypoxanthine can be an index of ATP supply–demand imbalance during exercise. The present study determined the effects of hypoxic exercise conditioning on work capacity, blood lactate, plasma hypoxanthine and various neurohormonal factors.2. Blood lactate, plasma hypoxanthine and neurohormonal factors (catecholamines, renin–angiotensin system activity and natriuretic peptides) were measured at rest and after maximal cardiopulmonary exercise testing (at sea level) both at pre- and post-hypoxic exercise conditioning in six males (40±2 years). The training protocol consisted of ergometer exercise twice weekly for 40 min in a hypobaric chamber (61.7–47.2 kPa) for 3 weeks.3. Pulmonary function and haematological and echocardiographic parameters were not altered after hypoxic exercise conditioning. Work rate at peak exercise (264±10 vs 321±31 W; P = 0.10) tended to be increased and peak O2 pulse (15.0±1.0 vs 18.4±1.4 mL/beat; P 〈 0.05) increased after exercise conditioning. The double product during submaximal exercise decreased and systolic blood pressure at peak exercise increased after exercise conditioning. Resting and exercise neurohormonal factors were unchanged, except for reduced resting plasma adrenaline levels. Blood lactate at peak exercise (7.4±0.7 vs 4.8±0.5 mmol/L; P 〈 0.05) became lower and peak plasma hypoxanthine (43.2±5.7 vs 26.4±5.0 μmol/L; P 〈 0.1) tended to be decreased after exercise conditioning.4. Hypoxic exercise conditioning tended to increase maximal power output with a decrease in exercise blood lactate and a trend towards a decrease in exercise plasma hypoxanthine. These data suggest that exercise conditioning under simulated altitude may improve ATP supply–demand imbalance during exercise with less anaerobiosis, which could contribute to enhanced endurance performance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1440-1681.1999.03034.x
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  • 4
    Electronic Resource
    Electronic Resource
    AUGMENTED EXERCISE PLASMA NORADRENALINE WITH IMPAIRED CHRONOTROPIC RESPONSIVENESS IN PATIENTS WITH HYPERTROPHIC CARDIOMYOPATHY (1998)
    Oxford, UK : Blackwell Publishing Ltd
    Clinical and experimental pharmacology and physiology 25 (1998), S. 0 
    Details
    ISSN: 1440-1681
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: 1. There is controversy regarding plasma catecholamine levels in patients with hypertrophic cardiomyopathy (HCM) and few data exist on serial plasma catecholamine measurements during exercise. The present study determined whether cardiovascular and plasma catecholamine responses to exercise were altered in patients with HCM.2. Plasma noradrenaline (NA) and adrenaline were measured at rest, at the end of each stage during exercise and immediately and 5 min after submaximal treadmill exercise in 15 patients with non-obstructive HCM (13 males, two females; mean (±SEM) age 54 ± 3 years) and in 15 age- and sex-matched controls. The ratio of the increment in heart rate (HR) divided by the increment in plasma NA during exercise (ΔHR/ΔNA) was used as an index of chronotropic sympathetic responsiveness to exercise.3. Exercise duration was shorter (11.2 ± 0.6 vs 8.7 ± 0.6 min for control vs HCM, respectively; P〈0.01) and diastolic blood pressure was significantly higher at stages I and II of modified Bruce protocol HCM.4. Resting plasma NA levels (149 ± 17 vs 167 ± 28 pg/mL for control vs HCM, respectively; NS) were not different, but plasma NA levels at stages I and H were significantly higher in HCM than in controls (243 ± 26 vs 399 ± 69pg/mL (P〈0.05) and 308 ± 30 vs 548 ± 110pg/mL (P〈0.05), respectively).5. Peak plasma NA levels were not significantly higher in HCM than in controls (578 ± 59 vs 918 ± 184 pg/mL, respectively; NS).6. The ratio AHR/ANA was significantly lower in HCM compared with control at stages I and II (0.49 ± 0.10 vs 0.21 ± 0.05 (P〈0.05) and 0.38 ± 0.06 vs 0.20 ± 0.05 (P 〈 0.05), respectively). There were no differences in plasma adrenaline responses during exercise between the two groups.7. Patients with HCM had augmented plasma NA levels during submaximal exercise with a higher diastolic blood pressure response. Chronotropic sympathetic responsiveness was impaired during the early stages of exercise in patients with HCM.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1440-1681.1998.tb02177.x
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  • 5
    Electronic Resource
    Electronic Resource
    A finite element analysis of a free surface drainage problem of two immiscible fluids (1989)
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 9 (1989), S. 569-582 
    Details
    ISSN: 0271-2091
    Keywords: Flow analysis ; Free surface problem ; Finite element method ; Blast furnace ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A sharp interface problem arising in the flow of two immiscible fluids, slag and molten metal in a blast furnace, is formulated using a two-dimensional model and solved numerically. This problem is a transient two-phase free or moving boundary problem, the slag surface and the slag-metal interface being the free boundaries. At each time step the hydraulic potential of each fluid satisfies the Laplace equation which is solved by the finite element method. The ordinary differential equations determining the motion of the free boundaries are treated using an implicit time-stepping scheme. The systems of linear equations obtained by discretization of the Laplace equations and the equations of motion of the free boundaries are incorporated into a large system of linear equations. At each time step the hydraulic potential in the interior domain and its derivatives on the free boundaries are obtained simultaneously by solving this linear system of equations. In addition, this solution directly gives the shape of the free boundaries at the next time step. The implicit scheme mentioned above enables us to get the solution without handling normal derivatives, which results in a good numerical solution of the present problem. A numerical example that simulates the flow in a blast furnace is given.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/fld.1650090507
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  • 6
    Electronic Resource
    Electronic Resource
    A finite element solution of a tidal current problem in the seto inland sea by using the ICCG method (1985)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 21 (1985), S. 1427-1445 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: When the finite element method is applied to the analysis of tidal currents in an inland sea with many islands, a system of linear equations with large band and sparse coefficient matrix is solved at each time step, and therefore the finite element methods usually suffer a severe economic disadvantage for practical calculations. The method used in this paper for solving a system of linear equations with large band and sparse coefficient matrix is the incomplete Cholesky conjugate gradient (ICCG) method: The ICCG method was compared with other methods such as the Gaussian elimination method, the Gauss-Seidel method and the conjugate gradient method. This method showed significant improvement in computation time and it can overcome the disadvantage that the efficiency to solve the matrix equations which appear in the finite element analysis of tidal currents usually diminishes as the bandwidth grows. The simulation results of tidal currents in the Seto Inland Sea of Japan were compared with field data and good agreements were obtained.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620210806
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